Protein powder is more popular now than it has ever been, with a surprisingly large increase in sales to women. Even just a few years ago, the popular perception of protein powder was that it was something that only bodybuilders or athletes would use.
But thanks to clever marketing from supplement campaigns, and a large switch in public opinion/knowledge about women lifting heavy weights protein powder is now a common supplement for women.
While younger women may feel no stigma in taking a traditionally “male” supplement, older women are less likely to start taking it. This is a problem, because the older you are, the more protein you need.
A 2012 study on elderly men found that as you age the anabolic response to protein ingestion is reduced, meaning that elderly men and women require more protein than younger men and women (1).
Protein powder increases overall protein intake. You could get the same benefits from a high protein diet without whey protein (or casein, soy, or hemp). But the simple fact is that without protein powder, most people struggle to get anywhere near their protein requirements.
A 2010 study by Wright & Wang found that the average protein intake for men was 15.9% while women only managed 15.5% (2).
Another study in 2008 found that the average American was nowhere near their recommended intake (3).
Protein powders are easy to transport, easy to store, taste nice (usually), are adaptable to different recipes, and can be prepared in seconds. So in a lot of ways, protein powders really are responsible for any benefits of a high protein diet.
Increased protein intake can increase muscle growth. One of the most well documented benefits of protein is its effect on muscle growth. Exercising without sufficient protein intake will lead to poor muscle growth, and potentially muscle loss. But if you increase your protein intake to match, you will create a positive muscle protein balance which will lead to muscle growth (4).
It is partly for this reason that athletes require more protein than regular (non-athletic) people. A study in 1992 found that strength athletes require twice as much protein as sedentary people do (5).
This is partly due to the need for increased muscle mass, but also for recovery. Female athletes (even amateur ones) need to fully recover from gym sessions, or sporting events.
Protein can help to improve recovery. Poor recovery can cause a lot of issues for anyone training at a high intensity, and proper protein intake is a large part of that. A study in 1997 found that exercise can increase muscle protein net balance for 48 hours afterwards, this means that you need to ensure you have adequate protein for two days after exercise (6).
Protein powder can elevate protein synthesis. Taking protein in the hours after a workout will elevate protein synthesis almost instantly helping the body to begin the process of repair and re-growth of damaged muscle fibres (7).
But protein powder is not just beneficial for women who train for strength or hypertrophy. In fact it is rarely marketed as such. Protein powder has been shown to be effective at promoting fat loss.
Protein powder can help reduce body fat. A study in 2015 found that a combination of whey protein and resistance exercise was more effective at reducing body fat than taking carbohydrates after exercise (a common practice) (8).
The study also found that whey protein helped people to maintain fat free mass (muscle) better. In fact the protection of fat free mass during a diet is one of protein powders’ most important benefits.
A calorie deficit diet is the only way to lose weight, whether you create that deficit through diet alone, increased exercise, or a combination of the two (recommended). As the energy balance becomes negative the body uses stored energy (adipose tissue – or body fat as we know it) to keep our metabolism in order. This leads to a reduction in adipose tissue and a leaner body.
Sadly it’s not as easy as that, if you’ve ever looked at people who have been starved they don’t tend to look incredibly ripped with amazing abs. This is because a prolonged calorie deficit doesn’t just reduce body fat, but it can also reduce muscle mass.
Whatever your thoughts on women with muscles, losing muscle mass during a diet is not the solution. It is unpleasant, the results are awful, and your metabolism will be altered.
Keeping protein levels high can help to prevent the loss of muscle mass during a diet. Or more specifically it can limit any muscle loss to the smallest amount possible (if you are on a prolonged diet you’ll still lose a small amount of muscle mass).
A study in 2013 found that consuming double your protein intake (just like the athletes in the 92 study mentioned earlier) could protect muscle mass during short-term weight loss diets (9).
Another benefit of taking protein powder while on a diet is the high protein to calorie ratio, when you are trying to keep protein high but your calorie targets are low, then food choices become important. Peanut butter is technically high in protein, but the ratio of protein to calories is very low.
100g of peanut butter will provide 25g of protein, but is 588 calories. Compare that to a protein shake which can also contain 25g of protein but is only 114 calories (for example).
Whey protein (and other protein powders) is effective at increasing satiety – how full you feel after a meal. This is perfect for weight loss diets as it may prevent overeating or snacking between meals. It can also mitigate for lower calorie meals.
One study found that whey protein reduced short term food intake compared to a placebo group, and compared to carbohydrates (10).
This is partly down to amino acids that are released after the whey protein shake has been digested, and partly down to whey protein being insulinotropic. In other words whey protein stimulates the production of insulin which signifies that the meal is over by regulating blood sugar.
Protein may help improve metabolic health. According to McGregor & Poppitt (2013) milk protein (whey or casein) has been linked with improved metabolic health, and a reduction in the chances of Type II Diabetes (11).
The study claims that this stems from both direct and indirect benefits of dairy protein.
So just as we mentioned above, the increase in fat loss through raised satiety, increased muscle mass, and protection of muscle mass during a diet all indirectly reduce the risk of Type II Diabetes. While the direct effect of whey and casein protein on hypertension, and on insulin can help to reduce the risk of many metabolic diseases (including Type II Diabetes).
Soy Protein powder can reduce oxidative stress. It’s not just whey protein that is effective though, other proteins such as soy can also have benefits. A study in 2004 by Brown, DiSilvestro, Babaknia, & Devor compared whey protein, soy protein, and no protein intake after exercise (12).
It found that soy protein powder, but not whey, was effective at preserving anti-oxidant function after exercise. This means that taking soy protein powder after a workout can reduce oxidant stress, which occurs during intense workouts (13).
That being said, in a couple of studies where they compared whey protein and soy protein, the researchers found that whey protein was more effective than soy protein at increasing weight loss. The first study was published in 2011 and was performed on overweight and obese adults over 23 weeks.
It found no change in body composition in the soy protein group but the whey protein group had lost between 1.8 and 2.3kg (14).
The second study was performed on both young men and young women (18 female, 9 male) (15).
It found that when using larger amounts of both whey and soy protein powder led to similar results regardless of which you picked. So if you are going to choose soy protein over whey protein, then use larger doses.
While on the subject of milk based protein powders, a 2007 study found that milk based protein supplementation can help to increase bone mineral density in young women (16).
There are many forms of protein powder out there, but the most commonly used one is whey protein. As such, this section will concentrate more on whey protein than any other. Not only is whey protein the most commonly used protein powder, it is also the most often studied.
Because of this, we have a lot of evidence to back up the following statement: Whey protein is one of the safest supplements in existence.
There are very few side effects from taking whey protein (or any protein powder), and most of the commonly believed side effects are incorrect. But before we get into that, let’s examine some actual side effects of whey protein powder.
Protein powder can cause bloating. There has been some evidence of bloating, but this is usually caused by people having a mild milk allergy. In fact, there are lots of studies that document there being absolutely no bloating, diarrhea, or nausea in any of the subjects.
For example, this study on young women found no evidence of bloating, nausea, or diarrhea in any of the subjects over a 6 month period of taking milk based protein powder (17).
Protein powder can increase insulin resistance – This is by no means a certainty, but at least one study has claimed that whey protein may lead to insulin resistance (a leading cause of Type II Diabetes). The study was performed in 2002 and found that “plasma amino acid elevation induces skeletal muscle insulin resistance in humans” (18).
However the study had multiple flaws, and flies in the face of other studies that have found whey protein to help prevent Type II Diabetes.
Protein powder can increase mortality – In 2014 a study by found that people on low protein diets (aged under 65) were more likely to live longer and less likely to get cancer (19).
Other studies have demonstrated that whey protein stimulates mTOR and IGF-1, which when chronically stimulated can result in reduced life span (20).
But before we get carried away, the 2014 study found that higher protein intake in the elderly actually improved their lifespan and reduced the risk of cancer.
Also, while chronic stimulation of mTOR and IGF-1 can result in reduced life span, the amount of protein required to create that situation would be much more than the recommended dosage. Realistically, nobody has yet died from chronic whey protein consumption.
Protein powder can be stressful for the kidneys – For years one of the most common myths about protein powders was that too much was bad for your kidneys. There is even some evidence to support this, a 2011 study (on rats) found that a high protein diet caused alterations in renal health (21).
But even this study found that resistance exercise provided a protective effect.
In 2011 the World Health Organisation (WHO) came out and said that renal failure is not due to high protein diets, but is in fact a natural side effect of the decline in protein intake as you get older (22).
In people with healthy renal systems a high protein diet is perfectly safe, and may even be beneficial. However, if you already have a kidney issue then you should avoid a high protein (or even medium protein) diet (23).
Protein powder can have an effect on pregnancy – A study on mice found that a high protein diet led to smaller birth weight than a low protein/high carbohydrate diet (24).
But, considering that whey is found in cheese and milk and these are two very commonly consumed products by millions of pregnant women, it is unlikely to be an issue. Unless you are consuming a 70% protein diet.
The truth is that whey protein and all protein powders are pretty much the safest foods/ supplements that you could hope for. If you have a milk allergy then you may find bloating, nausea, and diarrhea to be an issue, but swapping to rice protein, pea protein, or hemp protein powder instead would prevent any issues.
There doesn’t seem to be any real danger to your health from following a high protein diet, no matter what some studies indicate. There has been no causal link found between high protein and mortality, and considering the hundreds of benefits that protein has it seems unlikely that we will find one.
The recommended amount of protein that you should take differs depending on who you ask, and ultimately on who you are. A study in 2013 looked at recommended daily amounts of protein for elderly people, they found that between 1 to 1.2g of protein per kg of body weight was sufficient per day for people aged over 65 (25).
But the study also found that elderly people who were suffering with severe chronic diseases require even more protein, perhaps up to 1.5g per kg.
On the other end of the spectrum, a study by Helms, Aragon, & Fitschen published in 2014 looked at natural bodybuilders. The study found that the optimal level of protein intake for a natural bodybuilder would be between 2.3-3.1g of protein per kg of lean body mass (slightly different to the above study which used bodyweight) (26).
Now most women are not natural bodybuilders, though it is becoming more and more common.
Examine.com states that sedentary individuals should aim for 0.8g of protein per kg, while active people should hit 1-1.5g per kg. Highly active people should aim for between 1.5 and 2g per kg (27).
As you can see, a lot of well respected sources offer completely different recommended dosages. As such, we will combine all three and give out a rough guideline. Considering the high safety of protein powder and high protein diets this should be fine.
If you are over 65 years old then you should aim for around 1.5g of protein per kg of bodyweight. If you are inactive and over 65 you could hit 1 to 1.2g. If you are under 65 you could take between 1.5 and 2g of protein, while if you are a natural bodybuilder you can hit 2.3+g per kg.
Now we have an idea of how much protein you can have per day, we should look specifically at protein powders. A study in 2013 found that a serving of 20g of whey protein was sufficient for maximal stimulation of protein synthesis (28).
But this was in younger people, a study on the elderly found that instead of 20g, a serving of 35g of whey protein was required for maximal stimulation of protein synthesis (29).
The reason for this, is due to the anabolic response to protein ingestion being reduced in the elderly. Studies have shown that older people require more Leucine, which whey protein is high in (30).
So if you are a 70kg 30 year old, active woman your protein requirements would be around 2g per kg or 140g per day. Of that 140g, a large percentage should come from foods such as meat, dairy, and fish (or vegetarian equivalents).
You could consider taking a protein shake in the morning alongside breakfast, and a casein protein shake before bed. Studies have shown casein to be more effective than whey when taken before sleep (31).
Q: Is protein good for weight loss?
A: Replacing meals with protein shakes may help you reduce your daily calories, which can help you lose weight
Q: How much protein should women get per day?
A: The US Department of Agriculture recommends that all men and women over the age of 19 should get at least 0.8 grams of protein per kilogram of body weight per day (or 0.37 grams per pound). That means a woman who is 130 pounds should get at least 48 grams of protein.
Q: Is whey or casein better?
A: Neither is better as they both serve different purposes. Whey protein is best post workout to promote recovery. Casein is best as a meal replacement since it’s more filling and slowly releases protein into the blood stream.
Q: Do protein shakes cause weight gain?
A: Weight gain occurs when you eat more calories than you burn. If your daily protein shake contains just 200 calories, it could result in a gain of 21 pounds in a year.
Q: Do protein shakes make you fart?
A: Sometimes protein can cause intestinal distress leading to protein farts. Taking a probiotic or a high quality protein powder should remedy this. You may need to switch to a different type of protein if it persists.
Q: Is soy protein bad for women?
A: Women aren’t at risk as much as men are from the negative affects of soy so moderate consumption is safe. However long term over consumption has been shown to cause cancer.
Protein powder is an excellent tool for any woman, whether they are young or old, overweight or underweight, active or sedentary.
Protein powder is safe to use, easy to transport, adaptable to different meals and snacks, and quickly absorbed. There are many health benefits too, ranging from strength and fat loss benefits, to reduced risk of metabolic diseases, strengthened bones, and overall health.